Did researchers find a new branch on the tree of life in Lake Vostok?

Reports that it's entirely new are a bit premature.

A slew of press reports have trumpeted the finding of a new strain of bacteria recovered from Lake Vostok. Vostok is located in Antarctica, where the liquid water is buried under several kilometers of ice that have kept it isolated from the outside environment for millions of years. After several years of efforts and a pause to work out decontamination procedures, a Russian team drilled down to the lake water for the first time last year.

The hope was that, like several other under-ice ecosystems (most notably the one that creates Blood Falls), Vostok would host a community of bacteria that scrapes out a living through some combination of residual organic material and energy provided by geological processes. According to the press accounts, that hope seems to have been borne out.

But what sort of life are we looking at? Almost all of the accounts trace back to a RIA Novosti account that has very little in the way of details. The Russian researchers have apparently sequenced some DNA from the organism; although they don't specify which DNA, chances are good that it's the gene for ribosomal RNA, which is very useful for placing the organism within the tree of life. The differences with known species of bacteria indicate that it's clearly a new species, and the initial analysis suggests that it doesn't even group neatly with any of the major categories of bacterial life we're aware of.

But claiming it's a whole new branch off the tree of life should probably require more extensive sequencing of other areas of the genome. More data could probably tell us something about how it ekes out a living in a frigid, isolated ecosystem, and help figure out what its closest relatives are.

To be clear, it almost certainly has some relatives. One of the scientists is quoted as saying, “If it were found on Mars, people would call it Martian DNA. But this is DNA from Earth."

As noted in the article, however, the match between its DNA and known species on Earth reached at least 85 percent in some stretches, clearly showing its kinship to this planet's other biological inhabitants. And Vostok has only been separated from the rest of that life for fewer than 30 million years. That's a long time by almost any standard, but less than one percent of the time that bacterial life has been evolving on Earth.

I don't know why... but my mind is filled with images of the old G.I. Joe cartoon with the gigantic city eating germ, Bacteria X, in which they had to create apple cannons in order to defeat it. Yeah, apple cannons... for the cyanide.

Interesring discovery, but I can't imagine too much environmental change happening that far under the ice to prompt any extreme adaptions in the bacteria.

OK, but assuming this was not a unique development of life (as the article says, p < 1E-9), those bacteria GOT THERE from a time when the water was not isolated and then were subjected to a very sharp survivability gradient as the ecosystem closed and cooled.

Having a single definition of survivability can speed the selection for various mutations. People who understand the science of evolution better than I might comment, but I note this little petri dish is very similar in its isolation and its hostility to outsiders, to the Galapagos Islands (which are mostly deserts), the poster-child for evolutionary obviousness.

Interesring discovery, but I can't imagine too much environmental change happening that far under the ice to prompt any extreme adaptions in the bacteria.

OK, but assuming this was not a unique development of life (as the article says, p < 1E-9), those bacteria GOT THERE from a time when the water was not isolated and then were subjected to a very sharp survivability gradient as the ecosystem closed and cooled.

Having a single definition of survivability can speed the selection for various mutations. People who understand the science of evolution better than I might comment, but I note this little petri dish is very similar in its isolation and its hostility to outsiders, to the Galapagos Islands (which are mostly deserts), the poster-child for evolutionary obviousness.

All it takes is the ability to hibernate and survive in a rock ejected from the planet Earth 20 million years ago.

If you were to catalog that finely you would discover, I'm sure, some people are more closely related to Chimpanzees than to other people, given the amount of similarity between the two species.

Nnnnnnnnno.

You really think all humans, even the chromosomally nonstandard ones, are closer to each other than any chimpanzee to any human?

Not the person to who you are responding, but I believe that. So does anybody else who has encountered the concept of phylogenetics. Yes, any human is more closely related to any other human than any chimpanzee.

Maybe not. Maybe, in a form of life that has been locked away in ice for millions of years, we've finally found the perfect neutral jury members to decide whether rounded rectangles, 3G algorithms and bounce-scroll effects are patentable.

If you were to catalog that finely you would discover, I'm sure, some people are more closely related to Chimpanzees than to other people, given the amount of similarity between the two species.

Nnnnnnnnno.

You really think all humans, even the chromosomally nonstandard ones, are closer to each other than any chimpanzee to any human?

All humans are equally related to all chimpanzees. In fact, all humans and chimpanzees descended from a common ancestor over 7 million years ago, at a specific moment in time. Our lineages diverged at a precise moment in time, and have been diverging at a more or less constant rate ever since.

Yay! This really amps up the likelihood for life under similar ice moon conditions. Granted that the superoxygenated water would be an energy source if there was a simple redox sink (say, bedrock) and the recirculated organics would have been captured as the initial bacterial load, it tsill shows long term viability under analogous conditions.

The DNA divergence seems overblown, IIRC one may see ~ 60-70 % divergence between eukaryotes alone in the last 500 million years. (Though sadly I can't find a good reference on short notice. Oh, I can see the change rates, but there is more to it and I'm out of time for doing quick-and-dirty estimates.) The likelihood that it is the surviving orphan of a lineage heretofore unobserved is minute. More likely it derives from a bacteria (or archaea) within the known lineages, upon which 30 million years under extreme and different conditions than earlier life seen has worked its evolutionary changes.

I can't imagine too much environmental change happening that far under the ice to prompt any extreme adaptions in the bacteria.

From the RIA Novosti article: "Scientists suspected that unique species of extremophile microbes, sustained by geothermal heat and capable of surviving in Vostok’s extreme oxygen concentration, could have evolved in the lake."

Hypercryogenic (extreme cold) and hyperoxygenic (extreme oxygen concentration) conditions doesn't guarantee extreme adaptations, but it does guarantee extreme adaption. The likelihood that the extensive adaptations are unique are higher than average. See Walt French's comment.

I thought it was the case that scientists had not cataloged the majority of bacteria on earth. If so, isn't it hard to know how related it is to other bacteria?

You don't need a catalog to estimate divergence in the form of changed base pairs, chromosomal structure, et cetera. That gives you estimates of divergence times (changes in non-selected DNA) and divergence amount (changes in selected DNA).

You do need a catalog to root a lineage, which this is a representative of.

So some of the relatedness issue can be resolved quickly, some may take a while if you are unlucky.

Putrid Polecat wrote:

Also, has the bacteria also been shared with other teams in order to duplicate results?

Obviously not yet. This time the life form is so interesting, it will likely end up looked at by many others.

Most sequences in the databases may be (many times sequenced but) from one source. You have to estimate overall reliability once in a while, obviously. Same procedure as all databases, essentially.

If you were to catalog that finely you would discover, I'm sure, some people are more closely related to Chimpanzees than to other people, given the amount of similarity between the two species.

Nnnnnnnnno.

You really think all humans, even the chromosomally nonstandard ones, are closer to each other than any chimpanzee to any human?

All humans are equally related to all chimpanzees. In fact, all humans and chimpanzees descended from a common ancestor over 7 million years ago, at a specific moment in time. Our lineages diverged at a precise moment in time, and have been diverging at a more or less constant rate ever since.

That's not the way genetics or speciation works. It almost certainly occurred at approximately 7 million years ago. However, with the exception of sudden isolating events like individuals rafting over water, there is probably a period of time where there is some genetic sharing between two populations as they continue to diverge. It is more likely that there were thousands of years where there were occasional matings between the two populations.

If you were to catalog that finely you would discover, I'm sure, some people are more closely related to Chimpanzees than to other people, given the amount of similarity between the two species.

Nnnnnnnnno.

You really think all humans, even the chromosomally nonstandard ones, are closer to each other than any chimpanzee to any human?

All humans are equally related to all chimpanzees. In fact, all humans and chimpanzees descended from a common ancestor over 7 million years ago, at a specific moment in time. Our lineages diverged at a precise moment in time, and have been diverging at a more or less constant rate ever since.

That's not the way genetics or speciation works. It almost certainly occurred at approximately 7 million years ago. However, with the exception of sudden isolating events like individuals rafting over water, there is probably a period of time where there is some genetic sharing between two populations as they continue to diverge. It is more likely that there were thousands of years where there were occasional matings between the two populations.

Of course, neither humans nor chimpanzees were around at the time. There is an equal genetic distance between us and our last common ancestor with chimps as their is between chimps and the last common ancestor. Not only is a few thousand years less than nothing in the grand scheme of things, but the point of divergence isn't even within one of two species being compared.It's basically like asking which is more closely related to your 3rd cousin; you or your identical twin brother?

If you were to catalog that finely you would discover, I'm sure, some people are more closely related to Chimpanzees than to other people, given the amount of similarity between the two species.

Nnnnnnnnno.

You really think all humans, even the chromosomally nonstandard ones, are closer to each other than any chimpanzee to any human?

All humans are equally related to all chimpanzees. In fact, all humans and chimpanzees descended from a common ancestor over 7 million years ago, at a specific moment in time. Our lineages diverged at a precise moment in time, and have been diverging at a more or less constant rate ever since.

That's not the way genetics or speciation works. It almost certainly occurred at approximately 7 million years ago. However, with the exception of sudden isolating events like individuals rafting over water, there is probably a period of time where there is some genetic sharing between two populations as they continue to diverge. It is more likely that there were thousands of years where there were occasional matings between the two populations.

Of course, neither humans nor chimpanzees were around at the time. There is an equal genetic distance between us and our last common ancestor with chimps as their is between chimps and the last common ancestor. Not only is a few thousand years less than nothing in the grand scheme of things, but the point of divergence isn't even within one of two species being compared.It's basically like asking which is more closely related to your 3rd cousin; you or your identical twin brother?

That I pretty much agree with. I was only arguing against the concept that there is necessarily a specific point in time where before that point the populations mixed genes regularly and after that point the populations never mixed genes. For most speciation events, it is likely that there is an interim period (which could be pretty long) where matings are rare, but occur often enough that important genes could be traded after that initial divergence began. Neanderthal genes ending up in some human populations are a great example. That gene transfer occurred hundreds of thousands of years after the initial divergence between the two populations (both of which seem to have split away from Homo Erectus long before meeting up again).